1. Field of the Invention
The present invention relates to a roller which is exposed to a very heavy load, and is required to have a suitable elastic force and an abrasion resistance and is structured so as to mount a tire for high speed rotation and a heavy load such as in an escalator, a moving walkway and the like, in which a high level of safety is required, more particularly a roller mounted so that the tire and the bearing are not raced even when the heavy load is applied during starting of the rotation and during a sudden stop, and a method of producing the same.
2. Description of the Related Art
The conventional roller used for a rotating portion which rotates at a high speed, is exposed to a heavy load, and is required to have a suitable elastic force and an abrasion resistance and requires a level of safety of the highest priority for use, such as transfer rollers, elevators, guide rollers, escalators, moving walks and the like with the mounting of a synthetic resin tire. The roller of this kind is structured such that a synthetic resin tire is integrally adhered to a smooth outer peripheral surface of an outer race in the bearing. Further, the tire provided in this kind of bearing is required an abrasion resistance and a suitable elastic force together with a resistance against a high speed rotation and a heavy load. The roller structured such that the synthetic resin tire used in the rotating portion in which a safety is required in the highest priority given is mounted to the bearing and is formed in such a manner that the tire adhered to the outer race of the bearing in a surrounding manner is formed in two layers, a tire outer peripheral portion that is made of a soft synthetic resin to meet a requirement of the abrasion resistance and the elastic force and a tire base portion directly adhered to the outer race of the bearing is made of a hard synthetic resin to bear a resistance against the high speed rotation and the heavy load. It is suggested that a roller structured in such manner that the synthetic resin tire is integrally adhered to the bearing in a surrounding manner is mounted to the bearing and is constituted by hard and soft, two layer synthetic resin tire, and a method of producing the same.
Conventionally, in this kind of roller, structured such that the synthetic resin tire is adhered to the outer race of the bearing, the synthetic resin tire used as the tire is integrally adhered to the outer race of the bearing in a surrounding manner, which is used as elevators, escalators, transfer rollers, guide rollers, the moving walk and the like, and rotates at a high speed, is exposed to a heavy load, is used under a very severe condition, is required to have a suitable elastic force and an abrasion resistance in accordance with a usage, and is required to have a safety with the highest priority. Accordingly, in order to obtain a stronger adhesion, it is suggested the structure be made such that the outer race of the bearing and the synthetic resin tire are integrally bridge welded by cooling and hardening the synthetic resin temporarily and thermally dissolved on an outer peripheral surface of the outer race in place of simply bonding them by applying an adhesive material.
Further, in order that the tire adhered to the outer peripheral surface of the outer race in the bearing is integrally adhered to the outer race of the bearing in a stronger manner, there is suggested a roller structured such that the tire is constituted by two layers comprising a soft synthetic resin and a hard synthetic resin, an inner tire made of the hard synthetic resin is directly adhered to the outer peripheral surface of the outer race in the bearing so as to obtain a stronger adhesion force, and an outer tire made of the soft synthetic resin is adhered in such a manner as to overlap with the hard synthetic resin inner tire, whereby the tire having two layers is adhered to the outer peripheral surface of the outer race of the bearing in a stronger manner.
Further, in the roller to which this kind of synthetic resin tire is mounted, in order to integrally adhere the synthetic resin tire having the hard and soft two layers to the outer race of the bearing, this has been produced by a method of integrally providing the soft resin tire outer peripheral portion on the outer peripheral surface of the hard synthetic resin tire base portion in a surrounding manner after adhering the hard synthetic resin tire base portion to the outer race of the bearing.
Further, in a method of producing a synthetic resin wheel, there is suggested a producing method comprising steps of forming a tire portion by the soft synthetic resin having a forming temperature lower than that of a wheel portion and forming the wheel portion along an inner side of the tire portion by the hard synthetic resin having a forming temperature higher than that of the tire portion.
In this kind of conventional roller, the synthetic resin tire is integrally adhered to the outer peripheral surface of the outer race in the bearing. Further, since the outer peripheral surface of the outer race in this kind of bearing is formed in a smooth surface, a strong adhesion force over a certain level can not be expected by an interlinking of the adhesive material between the synthetic resin tire adhered by the adhesive material or the like and the outer peripheral surface of the outer race. Accordingly, the synthetic resin tire integrally adhered to the outer race can not stand against the heavy load and the high speed rotation over a certain level when being used in elevators, escalators and the like, so that the adhesion between the outer race and the tire is separated and the tire races on the outer race of the bearing. In the worst case, there is a problem that the tire is taken out from the outer race of the bearing so as to slip off.
Further, in order that the outer race of the bearing and the synthetic resin tire are more firmly adhered to each other, the structure is made so as to firmly adhere the synthetic resin tire on the outer peripheral surface of the outer race by cooling and hardening the temporarily dissolved synthetic resin on the outer race of the bearing in place of the adhesion by simply applying the adhesive material. In this structure, in comparison with the structure simply bonded by an application of the adhesive material, a strong adhesion force can be obtained, however, in this kind of roller used in elevators, escalators, transfer rollers and the like, since there is a case that a significantly heavy load is applied at a starting time or at a time of a sudden stop and a severe using condition that it is necessary to rapidly stop the high speed rotating roller at a time of high speed rotation or a sudden stop is required, there is a problem that the adhesion between the tire and the outer race of the bearing is damaged and peeled off during the use, so that the tire races on the outer race and falls off from the outer race.
Further, in order that the tire adhered to the outer peripheral surface of the outer race in the bearing is integrally adhered to the outer race of the bearing in a stronger manner, the structure is made such that a roller structured such that the tire is constituted by two layers comprising a soft synthetic resin and a hard synthetic resin, an inner tire made of the hard synthetic resin is directly adhered to the outer peripheral surface of the outer race in the bearing so as to obtain a stronger adhesion force, and an outer tire made of the soft synthetic resin is adhered in such a manner as to overlap with the hard synthetic resin inner tire, whereby the tire having two layers is adhered to the outer peripheral surface of the outer race of the bearing in a stronger manner. In this roller, in comparison with the structure made so as to integrally adhere the tire to the outer race by bonding the synthetic resin tire by an application of the adhesive material or cooling and hardening the thermally dissolved synthetic resin on the outer race, a more firm adhesion force can be obtained, however, a load of some hundreds kilograms per 1 cm 2 may be applied, and a high speed rotation of some thousands per 1 minute is required. Accordingly, the adhesion between the tire and the outer race of the bearing is damaged and peeled off during the use, so that there is a problem that the tire races on the outer race and falls off from the outer race.
Further, in a conventional method of integrally providing the soft resin tire outer peripheral portion on the outer peripheral surface of the hard synthetic resin tire base portion in a surrounding manner after adhering the hard synthetic resin tire base portion to the outer race of the bearing, when the soft synthetic resin tire outer peripheral portion is adhered onto the outer peripheral surface of the tire base portion in a surrounding manner, since a sealing performance of the tire outer peripheral portion with respect to the tire base portion is deteriorated, it is necessary to firmly bond the tire outer peripheral portion to the tire base portion by the adhesive material. Accordingly, a step of uniformly applying the adhesive material to all the surface of the outer peripheral surface with respect to the tire base portion is required and a problem results in that the roller itself is broken due to peeling off from the bonding portion when rotating at a high speed and under a heavy load in the case of bonding by the adhesive material. Further, there is a problem that a sufficient skill is required for uniformly applying the adhesive material on all the surface of the outer peripheral surface with respect to the tire base portion, a producing step is complex and a producing cost is increased.
Further, in the roller which is exposed to the heavy load and stopped for a sufficiently long time, such as in the escalator and the like, when using this kind of conventional roller to which the conventional soft synthetic resin tire is mounted, the synthetic resin tire can not stand against the heavy load while the rotating operation of the roller is stopped, so that there is a problem that the portion to which the load is applied is pressed, deformed and recessed (so-called an abraded out state) and an expansion is formed on the tire in front of and at the back of a rotating direction of the roller, thereby disturbing the rotation of the roller at the starting time.
Further, in the method of producing the synthetic resin wheel as disclosed in Japanese Patent Laid-Open No. 297606/1994, comprising the steps of forming the tire portion by the soft synthetic resin having a forming temperature lower than that of the wheel portion and forming the wheel portion along the inner side of the tire portion by the hard synthetic resin having a forming temperature higher than that of the tire portion, since the tire portion is formed by the soft synthetic resin having the forming temperature lower than that of the wheel portion and the wheel portion is formed along the inner side of the tire portion by the hard synthetic resin having a forming temperature higher than that of the tire portion, it is favorable that the soft synthetic resin tire portion and the hard synthetic resin wheel portion are integrally welded without using the adhesive material, however, it is necessary to mount the metal bearing by bonding to the inner side of the wheel portion of the integrally welded tire portion and wheel portion. Accordingly, in the roller for the escalator and the like in which the heavy load and high speed rotation, the abrasion resistance and a certain elastic force are required, there is a problem that the adhesion between the bearing and the wheel portion by the adhesive material is peeled off.
Further, in the method of producing the synthetic resin wheel as disclosed in Japanese Patent Laid-Open No. 297606/1994, comprising the steps of forming the tire portion by the soft synthetic resin having a forming temperature lower than that of the wheel portion and forming the wheel portion along the inner side of the tire portion by the hard synthetic resin having a forming temperature higher than that of the tire portion, since the wheel portion is integrally formed along the inner side of the tire portion and the bearing is later inserted and mounted to the wheel portion, the wheel portion can not be integrally welded to the tire portion and the bearing at a time, so that there is a problem that a step for mounting and fixing the bearing to the wheel portion is required.
Further, when it is intended to pour the hard synthetic resin having a forming temperature higher than that of the soft synthetic resin in the tire portion so as to charge and integrally weld for integrally welding the bearing with the wheel portion at the same time of providing the wheel portion in the inner side of the tire portion, that is, for forming the wheel portion between the tire portion and the bearing by the method of producing the synthetic resin wheel disclosed in Japanese Patent Laid-Open No. 297606/1994, comprising the steps of forming the tire portion by the soft synthetic resin having a forming temperature lower than that of the wheel portion and forming the wheel portion along the inner side of the tire portion by the hard synthetic resin having a forming temperature higher than that of the tire portion, a gas is generated on a contact surface between the poured hard synthetic resin and the soft synthetic resin in the tire portion, the tire portion and the wheel portion can not be completely welded all over the surface due to the generated gas, and only a part which is not influenced by the gas is welded, so that there is a problem that the tire portion and the wheel portion are peeled off when used in the escalator roller and the like which rotates at a high speed and is exposed to a heavy load.
An object of the present invention is to solve the technical problems of this type of conventional roller structured so as to integrally adhere the synthetic resin tire to the outer race of the bearing. In accordance with the present invention, there is provided a roller structured so as to more firmly and integrally adhere the synthetic resin tire to the outer peripheral surface of the an outer race of the bearing and is more firmly adhered without peeling off and the tire and the outer race of the bearing do not independently and freely rotate, that is, so as to prevent a rotation. Further, another object of the present invention is to solve the technical problem of the conventional method of producing the synthetic resin wheel and the method of producing the roller to which the overlaid synthetic resin tire is mounted as mentioned above. In accordance with the present invention, there is provided a roller and a method of producing the same comprising the steps of concentrically arranging a soft synthetic resin tire outer peripheral portion and a bearing which are previously formed at a gap and pouring a hard synthetic resin having a melting point higher than that of the tire outer peripheral portion into the gap so as to charge and form a tire base portion integrally welded with the tire outer peripheral portion and the bearing.
The inventors of the present invention have researched and solved the technical problems mentioned above in the conventional art, and as a result, have developed a roller to which the tire is mounted so as to be prevented from racing and a method of producing the same was developed.
A roller to which a tire is mounted so as to prevent racing in accordance with the present invention is characterize in that a synthetic resin tire overlaid in hard and soft layers is integrally adhered on an outer peripheral surface of an outer race in a bearing so as to be more firmly adhered without peeling off, one or a plurality of grooves having a fixed depth and width are spirally recessed on the outer peripheral surface of the outer race in the bearing in a surrounding manner so that the tire and the outer race of the bearing do not independently and freely rotate, that is, so as to more firmly and integrally adhere the tire to the outer race of the bearing in such a manner as to prevent rotation, and a part of the synthetic resin tire is inserted and welded within the grooves on the outer peripheral surface of the outer race in the bearing, thereby being adhered so that a more firm adhesion force can be obtained.
In accordance with the present invention, there is provided a structure in which one or a plurality of grooves are recessed on the outer peripheral surface of the outer race in the bearing, a tire base portion made of a hard synthetic resin is integrally adhered to all the peripheral surface of the outer peripheral surface in the outer race, and a tire outer peripheral portion made of a soft synthetic resin is integrally welded on all the peripheral surface of the outer peripheral surface in the tire base portion.
In accordance with the present invention, there is provided a structure in which one or a plurality of grooves are recessed on the outer peripheral surface of the outer race in the bearing, a tire base portion made of a hard synthetic resin is integrally adhered to all the peripheral surface of the outer peripheral surface in the outer race, an adhered recessed surface is provided in a surrounding manner by forming the outer peripheral surface of the tire base portion in a circular arc shape, one or a plurality of grooves are recessed on an adhered recessed surface, and a tire outer peripheral portion made of a soft synthetic resin is integrally welded on all the peripheral surface of the outer peripheral surface in the tire base portion.
In accordance with the present invention, there is provided a structure in which a plurality of grooves are recessed on the outer peripheral surface of the outer race in the bearing in a surrounding manner by arranging in a spiral manner.
In accordance with the present invention, there is provided a structure in which a plurality of grooves are recessed on the outer peripheral surface of the outer race in the bearing in a surrounding manner in parallel and in a direction perpendicular to an axial direction of the bearing.
In accordance with the present invention, there is provided a structure in which one or a plurality of grooves are obliquely recessed on the outer peripheral surface of the outer race in the bearing in a surrounding manner at a fixed angle of incline with respect to an axial direction of the bearing in a spiral manner.
In accordance with the present invention, there is provided a structure in which a plurality of grooves are spirally recessed on the outer peripheral surface of the outer race in the bearing in a surrounding manner and the grooves are mutually crossed on the outer peripheral surface of the outer race.
In accordance with the present invention, there is provided a structure in which a thickness of the outer race of the bearing coincides with a size obtained by adding a depth of a groove portion of the groove to a thickness of an outer race of a standard bearing in accordance with an international standard.
A method of producing a roller to which a tire is mounted so as to prevent racing in accordance with the present invention comprises the steps of arranging a bearing having one or a plurality of grooves on an outer peripheral surface of an outer race with a gap concentrically provided in an inner side of a tire made of a soft synthetic resin, and pouring and charging a hard synthetic resin having a melting point higher than a melting point of a soft synthetic resin in a tire outer peripheral portion into a space formed between the tire outer peripheral portion and the outer race of the bearing so as to form a tire base portion, whereby the tire base portion is integrally welded to the bearing and the tire outer peripheral portion.
In accordance with the present invention, there is provided a method of producing a roller to which a tire is mounted so as to prevent racing comprising the steps of arranging a bearing having one or a plurality of grooves on an outer peripheral surface of an outer race with a gap concentrically provided in an inner side of a tire made of a soft synthetic resin having a melting point of 190xc2x0 C., and heating, dissolving, pouring and charging a hard synthetic resin having a melting point of 210xc2x0 C. into a space formed between the tire outer peripheral portion and the bearing so as to form a tire base portion, whereby the tire base portion is integrally welded to the bearing and the tire outer peripheral portion.
In accordance with the present invention, there is provided a method of producing a roller to which a tire is mounted so as to prevent racing comprising the steps of arranging a bearing having one or a plurality of grooves on an outer peripheral surface of an outer race with a gap concentrically provided in an inner side of a tire made of a soft polyurethane rubber having a melting point of 190xc2x0 C., and heating, dissolving, pouring and charging a thermoplastic hard polyurethane rubber having a melting point of 210xc2x0 C. into a space formed between the tire outer peripheral portion and the bearing so as to again dissolve and mix a part of the soft polyurethane rubber on the surface of the tire outer peripheral portion on a contact surface, thereby forming a tire base portion, whereby the tire base portion is integrally welded to the bearing and the tire outer peripheral portion.
In accordance with the present invention, there is provided a method of producing a roller to which a tire is mounted so as to prevent racing comprising the step of protruding an inner peripheral surface in an inside direction of the tire outer peripheral portion toward a center direction so as to form a circular arc inner peripheral surface having a cross section formed in a circular arc.
In accordance with the present invention, there is provided a method of producing a roller to which a tire is mounted so as to prevent racing comprising the step of spirally recessing a plurality of grooves on the outer peripheral surface of the outer race of the bearing to which the tire base portion is welded in a surrounding manner.
In accordance with the present invention, there is provided a method of producing a roller to which a tire is mounted so as to prevent racing comprising the steps of spirally recessing a plurality of grooves on the outer peripheral surface of the outer race of the bearing to which the tire base portion is welded in a surrounding manner, recessing the grooves in a direction perpendicular to the axial direction of the roller and in parallel in a surrounding manner, spirally and obliquely recessing at an angle of incline with respect to an axial direction of the bearing, or spirally recessing the grooves so as to cross the grooves to each other on the outer peripheral surface of the outer race.